1. Field of Invention
The present invention relates to an oil pump control method for a hybrid vehicle, and more particularly, to a technology configured to reduce operation noise of an electric oil pump.
2. Description of Related Art
An electric oil pump is additionally provided in a hybrid vehicle in addition to a mechanical oil pump to operate supplementarily when the mechanical oil pump cannot supply a sufficient oil flow to a transmission in an idle state or EV mode driving.
In operating the electric oil pump, when a driver switches a shift lever from step N to step D while stepping a brake, a pump controller controls rpm of the electric oil pump to increase in order to form line pressure required for shifting as shown in FIG. 1 and thereafter, when the shifting from step N to step D ends to decrease the required line pressure, the pump controller sends a command to decrease the rpm to the electric oil pump.
However, in the above case, as a load of the electric oil pump is decreased by the line pressure which decreases instantaneously, the electric oil pump rotates rapidly like a part marked with A and thereafter, the speed of the electric oil pump is decreased by the command of the pump controller in the end.
As described above, at the time when the shifting ends, as the load decreases, an overshoot phenomenon in which the rpm of the electric oil pump increases unexpectedly causes noise.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.